Thirty years ago, as the nation mourned the loss of seven astronauts on the space shuttle Challenger, Bob Ebeling was steeped in his own deep grief.

The night before the launch, Ebeling and four other engineers at NASA contractor Morton Thiokol had tried to stop the launch. Their managers and NASA overruled them.

That night, he told his wife, Darlene, “It’s going to blow up.”

When Challenger exploded 73 seconds after liftoff, Ebeling and his colleagues sat stunned in a conference room at Thiokol’s headquarters outside Brigham City, Utah. They watched the spacecraft explode on a giant television screen and they knew exactly what had happened.